The objective of this project is to determine the pattern of chromosomal changes in cancer, particularly in hematologic disorders such as acute and chronic myelogenous leukemia. The nonrandom patterns that are observed can then be correlated with (1) specific types of leukemia, (2) specific clinical signs evident during the initial phase of leukemia, and (3) clinical response of the patient to treatment. We recently summarized our data regarding 50 patients with acute nonlymphocytic leukemia and showed that patients with acute myelocytic leukemia and a normal karyotype had a survival of only 2 months. Patients with acute myelomonocytic leukemia showed no such correlation between karyotype and clinical course. Moreover, we observed that the only two patients in this series with acute promyelocytic leukemia, were the only two who had an abnormality of No. 17. Further study of hhis abnormality in 3 more patients has shown that it is a translocation between Nos. 15 and 17 (t(15;17)(q22;q21)). In addition we have studied 13 patients with acute leukemia after treatment of either malignant lymphoma (11) or multiple myeloma (2). All patients had an abnormal karyotype; in nine patients loss of part of all of one No. 5 was seen, and in six patients an abnormality of No. 7 was detected.